This simple tool makes use of System.Security.Cryptography.ProtectedData to encrypt data per machine (e.g. to protect configuration sections or certain values of configuration-keys).
ProtectedData in this case operates on machine level. So one needs to recreate the encrypted data on every machine the configuration should be used on.
For better "data exchange" the string is additionally encoded as Base64-string.
CustomSoft.AppConfigSecurityHelper.exe encrypt TehSecretKey TheDataToEncryptAsString
CustomSoft.AppConfigSecurityHelper.exe decrypt TehSecretKey AQAAANCMnd8BFdERjHoAwE/Cl+sBAAAAKGFSrmM/OkGBk6KFhhQzrgQAAAACAAAAAAADZgAAwAAAABAAAAAO8oCByALV94R/j7Q8s6PYAAAAAASAAACgAAAAEAAAAG6vDJxPuW9VUnRPYtQpvvoQAAAApMTSVm2R1/ZRRvhEwZ3qXBQAAACkDSCGCC+NnnuAI8ZcVGMw5kjhZA==
Note: One can only decrypt this base64 string on the machine it was encrypted (or the configured machine key on that machine).